The present invention relates to a system for the transmission of information by degrees, particularly remote control information, for example for urban boiler rooms, commercial centres, factory workshops for paging isolated staff, and units of industrial exploitation in general, including a series of identical beacons, each comprising an emitter and a receiver tuned to the same frequency, the emitter being switched on as soon as a bit of information is received from another beacon, and means for cutting off the receiver as soon as the emitter is switched on, all the beacons thus being able to receive the same information simultaneously and each beacon being able to retransmit the information received from another to all the beacons not having received information.
It has already been proposed to operate from a central emitter and at one frequency, by modulation of a carrier wave by pulse signals.
The drawback of the central emitter lies, on the one hand, in the necessary power which it is obliged to develop and, consequently, in the saturation of the air space and, on the other hand, in the length of the necessary scrutinizing time. It has therefore been proposed to use a series of low-power emitters, or beacons. In fact, each beacon, for this transmission by degrees, possesses a receiver and an emitter. Transmission being effected at one frequency, each of the beacons receives, by its receiver, a signal which it detects and which it retransmits immediately, or after a very short phase shift, by its emitter. However, without any other arrangement, the receiver of each beacon would receive the signal again upon its emission by the emitter of this beacon. To avoid this phenomenon of looping, it has therefore been proposed to cut off the receiver of the beacons during their period of emission.
In addition, it was known to use only one type of signal, with the result that the detection of the leading edge of this signal, by the receiver of a beacon, sufficed for the retransmission of this signal by its emitter, its receiver being cut off.
Thus, a system of beacons was known, in which each beacon emits a signal towards all those which have not received it, being given that all those which emit have their receiver cut off and that this transmission by degrees, apart from the slight phase shift mentioned hereinabove, is instantaneous. In such a system, there is no looping, the signal progresses in the manner of a wave, from beacon to beacon, and all the beacons are virtually synchronous.
Heretofore, the information at each beacon was processed before being retransmitted. This resulted in a loss of time. In addition, this retransmission was effected only after an information signal or word was received completely. This was another reason for loss of time.